Conventionally, a receiver includes an antenna, which receives a wireless signal, and a processing unit. The processing unit is connected to the antenna by a signal line and obtains information from the wireless signal received by the antenna. In the receiver, when breaking has occurred in the signal line that connects the antenna and the processing unit, the wireless signal received by the antenna is not supplied to the processing unit. In such a case, the receiver does not work. Accordingly, the receiver includes a breaking detecting device that detects the occurrence of breaking in the signal line between the antenna and the processor.
Japanese Laid-Open Patent Publication No. 2000-49718 describes a conventional example of a breaking detecting device. The breaking detecting device includes a supply circuit for supplying a direct current to an antenna via a resistor, and a breaking detector for detecting a current that flows to the resistor from the supply circuit and determining whether breaking has occurred in the signal line connected with the antenna. When breaking has not occurred, the supply circuit forms a closed circuit. Thus, the breaking detector detects a current corresponding to the voltage applied to the resistor. When breaking has occurred, the supply circuit does not form a closed circuit and thus current does not flow to the resistor. Thus, the breaking detector does not detect a current. In this manner, the breaking detector detects whether breaking has occurred based on the current supplied from the supply circuit.